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Discussion Starter #1
I have a 1990 Sentra Automatic. I have been reading some other threads on what could be wrong, but I can't make much sense of it. The fuel filter is a year old, the spark plugs and wires are about 2 months old, I have a new alternator, new starter switch, a new starter, and a new battery. Yet still, when I start my car up. it will run for a few seconds, and then die. I must do this a few times with my foot on the gas to keep it from dying again. And still when I shift into reverse or drive, it dies. Also, when I do get it going, sometimes, my RPMs will fluctuate spontaniously, High-Low-Hig-Low, and the car lurches from the change in power. I need a basic explanation on what's wrong, and how to fix it... I want to do it myself as I am a student, and know a little something about cars. So any pictures or step-by-steps y'all could post would be much appreciated.
 

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I have a 1990 Sentra Automatic. I have been reading some other threads on what could be wrong, but I can't make much sense of it. The fuel filter is a year old, the spark plugs and wires are about 2 months old, I have a new alternator, new starter switch, a new starter, and a new battery. Yet still, when I start my car up. it will run for a few seconds, and then die. I must do this a few times with my foot on the gas to keep it from dying again. And still when I shift into reverse or drive, it dies. Also, when I do get it going, sometimes, my RPMs will fluctuate spontaniously, High-Low-Hig-Low, and the car lurches from the change in power. I need a basic explanation on what's wrong, and how to fix it... I want to do it myself as I am a student, and know a little something about cars. So any pictures or step-by-steps y'all could post would be much appreciated.
This type of driveability problem is seldom fixed on a forum like this. Too many things can cause the symptoms you've described. But from what you've described, my best guess is that possibly your air mass meter is bad. First check to make sure you don't have any vacuum leaks [missing, loose, or broken vacuum hoses] . You could try cleaning the hot wire of your air mass meter with carb cleaner too. Otherwise I'm thinking your air mass meter is at fault.
 

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it could be your TPS (throttle position sensor) however for the ga16is' it is located within the distributor...you might have to swap out the distributor...about 150 bucks for part...

good luck

-edit- correction....crankshaft position sensor is the one....
 

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Discussion Starter #4
Alright Guys, Problem solved... A friend and I flushed the cooling system, ran new Vacuum lines, and cleaned the Throttle Body. It seems to be Idleing fine now... The only problem is, It Idles around 1.8-2K RPM. My manual says it's supposed to idle around 900. I tried adjusting the screws, and it's as low as it will go, but it doesn't seem to change things. I remember reading somewhere about a wax coolant controlled idle device. Can anyone post pics or a write up telling me how to clean it?
 

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Alright Guys, Problem solved... A friend and I flushed the cooling system, ran new Vacuum lines, and cleaned the Throttle Body. It seems to be Idleing fine now... The only problem is, It Idles around 1.8-2K RPM. My manual says it's supposed to idle around 900. I tried adjusting the screws, and it's as low as it will go, but it doesn't seem to change things. I remember reading somewhere about a wax coolant controlled idle device. Can anyone post pics or a write up telling me how to clean it?
Just take off the coolant hoses going into and out of the wax type fast idle solenoid [near the throttle body linkage] Blow the brown coolant muck out of them with compressed air. Then reconnect and bleed the cooling system properly to make sure all of the air is out. Then it should come down off of the cold fast idle after it warms up.
 

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I'll bet you fixed the original problem by cleaning the throttle body [and hence the air mass meter wire under the screen]. I mentioned that in my first reply.
 

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Discussion Starter #7
I've been really busy latley and I havn't had a chance to clean the fast idle solenoid yet, I should have some time this weekend.

Another thing (sorry if it seems like I ask too many questions) My engine has always rattled, its a persistant rattle that seems to get quiet as the RPM's rise. I'm convinced that the problem is in the Cylinder head, I'm going to be taking the head apart this summer anyway (Putting in a Eurocam) Could anyone tell me what I should be looking for in the way of head damage or what could be causing the rattle? Thanks again

(Again, will flush out the Fast Idle Solenoid this weekend, I'll let you know how it goes)
 

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I've been really busy latley and I havn't had a chance to clean the fast idle solenoid yet, I should have some time this weekend.

Another thing (sorry if it seems like I ask too many questions) My engine has always rattled, its a persistant rattle that seems to get quiet as the RPM's rise. I'm convinced that the problem is in the Cylinder head, I'm going to be taking the head apart this summer anyway (Putting in a Eurocam) Could anyone tell me what I should be looking for in the way of head damage or what could be causing the rattle? Thanks again

(Again, will flush out the Fast Idle Solenoid this weekend, I'll let you know how it goes)
The rattle that goes away when revved up is usually the timing chain.
The Idle adjust screw is on the back of the throttle body, and very limmited space to get to. If it is idling too high, also check for vacuum leaks.
 
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